ProMag Steel/Polymer Rifle Magazine AR-15 9mm Colt/SMG Type 32-Round Black 32RD. The follower is injection molded and the magazine spring formed from heat treated chrome silicon wire. Specifications for ProMag Steel/Polymer AR-15 9mm Colt/SMG Type 32-Round Rifle Magazine: Manufacturer: ProMag Magazine Capacity: 32 Round Caliber: 9mm Luger Gun Model: AR-15 Features of ProMag Steel/Polymer AR-15 9mm Colt/SMG Type 32-Round Rifle Magazine Magazine body is constructed of a proprietary DuPont Zytel based polymer and heat treated steel with black oxide finish; steel upper polymer lower housing. Injection molded magazine follower Magazine spring formed from heat treated chrome silicon wire Package Contents: ProMag Steel/Polymer AR-15 9mm Colt/SMG Type 32-Round Rifle Magazine What firearm models does the manufacturer say ProMag Steel/Polymer AR-15 9mm Colt/SMG Type 32-Round Rifle Magazine is compatible with? The manufacturer says that ProMag Steel/Polymer AR-15 9mm Colt/SMG Type 32-Round Rifle Magazine is compatible with AR-15ProMag COL-A32-32RD: Steel/Polymer Rifle Magazine AR-15 9mm Colt/SMG Type 32-Round Black